.btn{
    display: inline-block;
    width: 100px;
    height: 30px;
    line-height: 30px;
    border: none;
    cursor: pointer;
    background-color: #FF6600;
    color: #ffffff;
}

.btn_default{
    background-color: gainsboro;
    color: white;
    width: 200px;
    height: 30px;
    line-height: 30px;
}
.btn_middle{

}
.btn_large{

}
.btn_group{
    .btn{
        margin-right: 20px;
        &:last-child{
            margin-right: 0px;
        }
    }
}